TWI570450B - An optical film, a method of manufacturing the same, and an image display device provided with the same - Google Patents

Description

Optical film, manufacturing method thereof and image display device therewith

The present invention relates to an optical film having a wavelength dispersion (reverse wavelength dispersion) in which a double wavelength is smaller and a double refraction is smaller in a visible light region, and an image display device including the optical film.

Optical members utilizing birefringence due to alignment of polymers are widely used in the field of image display. Among such optical members, there is a phase difference plate (retardation film) which is incorporated in a video display device, such as compensation of color tone and compensation of viewing angle. For example, in a reflective liquid crystal display device (LCD), there is a phase difference plate (λ/4 plate) using a retardation path length due to a phase difference due to birefringence as a wavelength. . In the organic EL display (OLED), an antireflection plate in which a polarizing plate and a λ/4 plate are combined is used in order to prevent reflection of external light (refer to Japanese Laid-Open Patent Publication No. 2007-273275). These optical members exhibiting birefringence are expected to be further expanded in the future.

Conventionally, the optical member mainly uses a cellulose derivative typified by triacetyl cellulose (TAC), a polycarbonate, a polycycloolefin, and the like. The shorter the wavelength of light, the greater the birefringence (i.e., the increase in phase difference). In order to make the image display device have excellent display characteristics, it is expected that the optical member can be reversed, and the shorter the wavelength of the display light, the smaller the birefringence (i.e., the phase difference is reduced). In the present specification, the shorter the wavelength of light in at least the visible light region, the smaller the birefringence of the wavelength dispersion, according to the name commonly used by the industry, and according to the general polymer and the optical member formed by the polymer. The characteristic shown opposite to the wavelength dispersion is called "reverse wavelength dispersion".

An optical member exhibiting reverse wavelength dispersion is disclosed in Japanese Laid-Open Patent Publication No. 2001-337222, which comprises a polymer having a positive intrinsic birefringence (polynorbornene) and a polymerization having a negative intrinsic birefringence. A phase difference plate made of a resin composition of a material (styrene polymer). Further, Japanese Laid-Open Patent Publication No. 2001-235622 discloses a copolymer of a molecular chain having a positive intrinsic birefringence (a decidene chain) and a molecular chain having a negative intrinsic birefringence (a styrene chain). The phase difference plate.

It is an object of the present invention to provide a novel optical film exhibiting reverse wavelength dispersion.

The optical film of the present invention has a layer composed of a resin (A) having a molecular structure represented by the following formula (1), (2) or (3) or a heterocyclic aromatic group, and The optical film exhibits, at least in the visible light region, the shorter the wavelength, the smaller the wavelength dispersion of the birefringence.

In the above formula (1), n is a natural number in the range of 1 to 4, and R ¹ and R ² are each independently a hydrogen atom or a methyl group.

The image display device of the present invention comprises the optical film of the present invention.

The optical film of the present invention exhibits reverse wavelength dispersion by having a layer composed of the molecular structure represented by the above formula (1), (2) or (3) or a resin having a heterocyclic aromatic group (A). .

The term "resin" in this specification is a broader concept than "polymer." The resin may be composed of, for example, one or two or more kinds of polymers, and may contain a material other than the polymer, for example, an additive such as an ultraviolet absorber, an antioxidant, a filler, a phase solvent, a stabilizer, or the like.

[Resin (A)]

The structure of the resin (A) is not particularly limited as long as it has a molecular structure represented by the above formula (1), (2) or (3) or has a heterocyclic aromatic group. When the molecular structure represented by the formulas (1), (2), and (3) and the heterocyclic aromatic group are the component structure X, for example, the resin (A) contains a composition having a molecular structure X bonded thereto. The polymer of the unit (repeated unit).

The resin (A) is, for example, an acrylic resin or a cycloolefin resin. An acrylic resin and a cycloolefin resin which have high transparency and mechanical properties and have an optical film of a layer composed of the resin (A), and are suitable as an optical film for an image display device such as a liquid crystal display (LCD).

The acrylic resin is a resin containing 50% by weight or more of the acrylic polymer, preferably 60% by weight or more, more preferably 70% by weight or more, and most preferably 80% by weight or more. The cycloolefin resin is a resin containing 50% by weight or more of the cycloolefin polymer, preferably 60% by weight or more, more preferably 70% by weight or more, and most preferably 80% by weight or more.

Among the optical films, there is a film (polarizing element protective film) for protecting a polarizing element in a polarizing plate. When the resin (A) has a molecular structure represented by the formula (1), the optical film of the present invention having a layer composed of the resin can be suitably used as a polarizing element protective film.

The polarizing element protective film is used in a state of being bonded to one side or both sides of the polarizing element. The polarizing element is typically formed by dyeing a polyethanol film with a dichroic substance such as iodine or a dichroic dye. Since an aqueous solution is used for dyeing, the polarizing element protective film bonded to the polarizing element is generally preferred to have water permeability. . The bonding of the polarizing element and the polarizing element protective film is one of the reasons why it is preferable to use a water-based adhesive or a polarizing element protective film to have water permeability. For example, a film composed of a cycloolefin polymer is hardly water-permeable because of its high hydrophobicity, and is not necessarily suitable as a polarizing element protective film. On the other hand, the molecular structure represented by the formula (1) has high hydrophilicity. Therefore, the content ratio of the structure in the resin (A) and the like may vary depending on the configuration of the specific optical film, and the optical film of the present invention having the layer composed of the resin (A) having the structure exhibits high water permeability. Therefore, it is suitable for the protective film of polarizing elements.

The resin (A) may have two or more molecular structures X.

Examples of the polymer having a constituent unit in which the molecular structure X is bonded include, for example, a unit represented by the following formula (4), (5) or (6) or α, β having a heterocyclic aromatic group. - Unsaturated monomer unit as a constituent unit of the polymer (B-1). In other words, the resin (A) may also contain a unit represented by the following formula (4), (5) or (6) or an α,β-unsaturated monomer unit having a heterocyclic aromatic group as a constitution. Unit of polymer (B-1).

In the formula (4), n is a natural number in the range of 1 to 4, and R ¹ and R ² are each independently a hydrogen atom or a methyl group.

Hereinafter, the unit represented by the formulas (4), (5), and (6) and the α,β-unsaturated monomer unit having a heterocyclic aromatic group are referred to as a constituent unit Y. Further, the α,β-unsaturated monomer unit having a heterocyclic aromatic group is described as an unsaturated monomer unit.

The units represented by the formulas (4), (5), and (6) in the unit Y are respectively composed of the molecular structures represented by the formulas (1), (2), and (3), and are combined by polymerization. A constituent unit formed by the polymerization of a vinyl group or a methyl group monomer. Further, the unsaturated monomer unit is typically a constituent unit formed by polymerization of a heterocyclic aromatic group by a monomer in which a polymerizable group is bonded to a vinyl group or a methyl group.

The constituent unit Y has a function of imparting a negative intrinsic birefringence to the polymer (B-1). By the action of the constituent unit Y, the optical film of the present invention thus exhibits reverse wavelength dispersion.

The effect of imparting a negative (or positive) intrinsic birefringence to a polymer means that when the unitary polymer is formed, the intrinsic birefringence of the formed homopolymer becomes negative (or positive). unit. The positive and negative intrinsic birefringence of the polymer itself depends on the combined effect of the birefringence produced by the unit and the birefringence produced by other constituent units of the polymer.

The positive and negative intrinsic birefringence of the polymer can be judged according to the following method: in a layer in which the molecular chain of the polymer is an axial alignment (for example, a plate or a film), the light perpendicularly incident on the main surface of the layer is parallel to The refractive index n1 of the layer of the vibrating portion of the alignment direction (orthogonal axis) of the molecular chain in the layer is subtracted from the refractive index n2 of the layer perpendicular to the vibrating portion of the alignment axis, that is, "n1-n2" . The value of the intrinsic birefringence can be calculated for the molecular structure of each polymer.

The positive and negative intrinsic birefringence of the resin depends on the combined results of the birefringence produced by the polymers contained in the resin.

The unit represented by the formula (4) is a lactam structure represented by the formula (1), and is formed by polymerization of a monomer (vinyl decylamine) in which a polymerizable group is bonded. The unit represented by the formula (4) is selected from the group consisting of N-vinyl-2-pyrrolidone units, N-ethylene-ε-caprolactam units, N-vinyl-2-piperidone units, N-ethylene-4-methyl At least one of a base-2-pyrrolidone unit, an N-ethylene-5-methyl-2-pyrrolidone unit, and an N-ethylene-ω-heptanoin unit.

The unit represented by the formula (5) is a unit of vinylanthracene. This unit is formed by polymerization of a green onion (vinyl onion) in which a polymerizable group is bonded to the onion structure represented by the formula (2). Further, a part of the hydrogen atom on the ring represented by the formula (5) may be substituted with a group exemplified as the organic residue in the following formula (8).

The unit represented by the formula (6) is a dibenzofulvene unit. This unit is a fluorene structure represented by the formula (3), and is formed by polymerization of a monomer (diphenylfulvene) in which a methyl group is bonded to a polymerizable group. Further, a part of the hydrogen atom on the ring represented by the formula (6) may be substituted with a group exemplified as the organic residue in the following formula (8).

The unit of the unsaturated monomer is not particularly limited, and for example, the heterocyclic aromatic group which the unit has is not limited. The hetero atom in the heterocyclic aromatic group is typically an oxygen atom, a sulfur atom or a nitrogen atom, and has an excellent effect of increasing the wavelength dispersion of birefringence in the polymer (B-1). Preferably, the nitrogen atom is used. When the wavelength dispersion of birefringence in the polymer (B-1) is increased, the degree of freedom in controlling the reverse wavelength dispersion in the optical film of the present invention is improved as the composition can obtain strong reverse wavelength dispersibility and the like. .

The heterocyclic aromatic group is, for example, at least one selected from the group consisting of a carbazolyl group, a pyridyl group, an imidazolyl group, and a thienyl group.

The unsaturated monomer unit is, for example, at least one selected from the group consisting of a vinyl carbazole unit, a vinyl pyridine unit, a vinylimidazole unit, and an ethylene thiophene unit.

The vinyl carbazole unit is represented by the following formula (7). Further, a part of the hydrogen atom on the ring represented by the formula (7) may be substituted with a group exemplified as the organic residue in the following formula (8).

The unsaturated monomer unit is preferably at least one selected from the group consisting of a vinyl carbazole unit and a vinyl pyridine unit, and has a particularly excellent effect of increasing the wavelength dispersibility of birefringence in the polymer (B-1). Good is a vinyl carbazole unit.

The polymer (B-1) may have two or more constituent units Y. When an optical film exhibiting reverse wavelength dispersibility is obtained, the resin (A) may contain a polymer other than the polymer (B-1).

Another example of a polymer having a molecular structure X-constituting unit may be a polymer having at least a part of a molecular structure or a functional gene molecular structure X and being denatured.

The polymer is, for example, a repeating unit having a hydroxyl group or a molecular structure X of an ethylene gene, and a cellulose derivative such as triethylene cellulose (TAC). By the combination of the molecular structure X, at least a part of the repeating unit of the cellulose derivative becomes effective in imparting a negative intrinsic birefringence to the derivative. The optical film of the present invention exhibits reverse wavelength dispersion by this action due to denaturation of molecular structure X.

[Optical film]

Hereinafter, specific examples of the optical film of the present invention will be described.

(Embodiment 1)

Fig. 1 shows an example of an optical film of the present invention. The optical film 1 shown in Fig. 1 is composed of a single layer 2, and the layer 2 is composed of a resin (A) containing a polymer (B-1) having a constituent unit Y. In the present embodiment, the intrinsic birefringence of the polymer (B-1) is a negative value, and the resin (A) further contains a polymer (B-2) having a positive intrinsic birefringence. The resin (A) contains a composition of the polymers (B-1) and (B-2).

The resin (A) contains a polymer (B-1) having a negative intrinsic birefringence and a polymer (B-2) having a positive intrinsic birefringence, and if the polymers of the two are aligned in the same direction, Since the slow axis (or fast axis) of each polymer is vertical, the birefringence of both sides will cancel. Here, the degree of cancellation by birefringence varies with wavelength, so that reverse wavelength dispersion of birefringence (for example, phase difference) occurs.

Although the optical film 1 is a single layer, it exhibits reverse wavelength dispersion. Therefore, the desired optical characteristics can be obtained by thinning, and the image display device including the optical film 1 can be further reduced in size and weight. Further, the optical film 1 realizes an optical film having a reverse wavelength dispersion property compared to a plurality of layers of the multiple layers, and the productivity is high because the bonding angle of each layer is not required to be adjusted.

When focusing on the alignment of the polymers (B-1) and (B-2), the optical film 1 is provided with a member formed of the resin A containing the polymer (B-1) and (B-2). As for the method of imparting the alignment of the resin (A), the film-forming resin (A) may be stretched.

The polymer (B-2) is not particularly limited as long as it has positive intrinsic birefringence.

The polymer (B-2) preferably has a ring structure in the main chain. By having a ring structure in the main chain, the glass transition temperature (Tg) of the polymer (B-2) and the resin (A) containing the polymer increases, and the optical film 1 having high heat resistance is obtained. Such an optical film having such high heat resistance can be disposed close to a heat generating portion such as a light source, for example, in an image display device. Further, since the processing temperature at the time of post-processing (for example, surface treatment such as coating) can be improved, the productivity of the optical film 1 becomes high.

The polymer (B-2) having a ring structure in the main chain and the Tg of the resin (A) containing the polymer are, for example, 110 ° C or higher. The Tg may be 115° C. or higher, 120° C. or higher, or even 130 depending on the type of the ring structure, the content of the ring structure in the polymer (B-2), and the content of the polymer (B-2) in the resin (A). Above °C. Tg can be obtained in accordance with JIS K7121.

The polymer (B-2) having a ring structure in the main chain is not particularly limited, and may be, for example, at least one selected from the group consisting of a cyclic olefin polymer and a cellulose derivative.

The polymer (B-2) may be a (meth)acrylic polymer, and in this case, an optical film having various properties such as optical properties, mechanical strength, moldability, and surface strength can be obtained.

The (meth)acrylic polymer (meth) acrylate unit accounts for 50 mol% or more of the total constituent unit (preferably 60 mol% or more, more preferably 70 mol% or more). The (meth)acrylic polymer may also contain a ring structure in a derivative of a (meth) acrylate unit. In this case, the total of the (meth) acrylate unit and the ring structure is 50% or more of the total constituent unit. , is considered a (meth)acrylic polymer.

When the polymer (B-2) is a (meth)acrylic polymer, the degree of freedom in controlling the reverse wavelength dispersion in the optical film 1 can be improved. The wavelength dispersion of the birefringence exhibited by the polymer (B-1) having the constituent unit Y as the main chain, compared with the birefringence of the polymer (B-2) of the (meth)acrylic polymer The wavelength dispersion is significantly larger. As described above, the degree of freedom in the control of the reverse wavelength dispersion can be improved by combining the polymer (B-1) and the polymer (B-2) having significantly different wavelength dispersion of birefringence.

The polymer (B-2) may also be a (meth)acrylic polymer having a ring structure in the main chain. As described above, by using a (meth)acrylic polymer having a ring structure in the main chain, the Tg of the polymer (B-2) and the resin (A) of the polymer rises to have high heat resistance. Optical film 1.

The (meth)acrylic polymer has a ring structure in its main chain, and is, for example, a ring structure having an ester group, a quinone imine group or an acid anhydride group.

More specifically, the ring structure may be selected from the group consisting of a lactone ring structure, a glutarmide structure, a glutaric anhydride structure, and an N-substituted maleimide (N-substituted). Maleimide) construction and at least one of maleic anhydride structures. The polymer (B-2) having a ring structure in the main chain exhibits a large positive intrinsic birefringence by alignment, so that the reverse wavelength can be further improved by combining with the polymer (B-1). The degree of freedom in the control of dispersion.

The ring structure is preferably at least one selected from the group consisting of a lactone ring structure and a pentylene imine structure, and more preferably a lactone ring structure. The polymer (B-2) having a lactone ring structure or a glutarylene imine structure, particularly a lactone ring structure, in the main chain has a very small wavelength dispersion of birefringence. Therefore, by combining with the polymer (B-1), the degree of freedom in control of the reverse wavelength dispersion can be further improved.

The specific lactone ring structure which the polymer (B-2) may have is not particularly limited, and may be, for example, a structure represented by the following formula (8).

In the formula (8), R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom or an organic residue having a carbon number of from 1 to 20. The organic residue may also contain an oxygen atom.

Examples of the organic residue include an alkyl group having a carbon number of from 1 to 20 such as a methyl group, an ethyl group or a propyl group; an unsaturated aliphatic hydrocarbon group having a carbon number of from 1 to 20 such as a vinyl group or a propenyl group; and a phenyl group and a naphthalene group; An aromatic hydrocarbon group having a carbon number of from 1 to 20; wherein the alkyl group, the unsaturated aliphatic hydrocarbon group, and the aromatic hydrocarbon group are at least one selected from the group consisting of a hydroxyl group, a carboxyl group, an ether group, and an ester group. A base replaced by a base.

The lactone ring structure represented by the formula (8) can be obtained, for example, by copolymerization of a monomer group containing methyl methacrylate (MMA) and methyl 2-(hydroxymethyl)acrylate (MHMA). Adjacent MMA units and MHMA units are subjected to dealcoholization and cyclization condensation. At this time, R ³ is H, R ⁴ and R ⁵ are CH ₃ .

The following formula (9) shows a quinodiimine structure and a glutaric anhydride structure.

In the formula (9), R ⁶ and R ⁷ are each independently a hydrogen atom or a methyl group, and X ¹ is an oxygen atom or a nitrogen atom. When X ¹ is an oxygen atom that is absent R ^8, R ⁸ is a hydrogen atom when X ¹ is a nitrogen atom, the carbon atoms of straight-chain alkyl group having 1 to 6, a cyclopentyl group, a cyclohexyl group or a phenyl group.

When X ¹ is a nitrogen atom, the ring structure represented by the formula (9) becomes a quinodiimine structure. The pentamethylene imine structure can be formed, for example, by amidation of a (meth) acrylate polymer by a guanamine reagent such as methylamine.

When X ¹ is an oxygen atom, the ring structure represented by the formula (9) becomes a glutaric anhydride structure. The glutaric anhydride structure can be formed, for example, by condensing and condensing a copolymer of (meth) acrylate and (meth)acrylic acid in a molecule.

The following formula (10) shows an N-substituted maleimide structure and a maleic anhydride structure.

In the formula (10), R ⁹ and R ¹⁰ are each independently a hydrogen atom or a methyl group, and X ² is an oxygen atom or a nitrogen atom. When X ² is oxygen atom, i.e. R ¹¹ is not present when X ² is nitrogen atom, R ¹¹ is a hydrogen atom, a linear-chain carbon atoms of the alkyl group having 1 to 6, a cyclopentyl group, a cyclohexyl group or a phenyl group.

When X ² is a nitrogen atom, the ring structure represented by formula (10) becomes an N-substituted maleimide structure. The acrylic resin having an N-substituted maleimide structure in the main chain can be formed, for example, by copolymerizing an N-substituted maleimide with a (meth) acrylate.

When X ² is an oxygen atom, the ring structure represented by the formula (10) becomes a maleic anhydride structure. The acrylic resin having a maleic anhydride structure in the main chain can be formed, for example, by copolymerizing maleic anhydride with a (meth) acrylate.

When the polymer (B-2) has a ring structure in the main chain, the ring structure content in the polymer (B-2) is not particularly limited, and is usually 5 to 90% by weight, preferably 20 to 90% by weight. . More preferably, the content ratio is more preferably from 30 to 90% by weight, from 35 to 90% by weight, from 40 to 80% by weight, and from 45 to 75% by weight. The content of the ring structure can be determined by the method described in JP-A-2001-151814.

The polymer (B-2) may have any constituent unit if its intrinsic birefringence is a positive value. For example, the polymer (B-2) may have a constituent unit Y. In this case, the compatibility between the polymers (B-1) and (B-2) is improved, and the optical film 1 having excellent transparency is obtained.

The polymer (B-2) can be produced by a known method.

In one example, the polymer (B-2) having a lactone ring structure in the main chain can be heated by the polymer (a) having a hydroxyl group and an ester group in the molecular chain in the presence of any catalyst. It is prepared by carrying out a condensation reaction of a lactone with a dealcoholation.

In the formula (11), R ¹² and R ¹³ are each a hydrogen atom independently or a group exemplified as an organic residue in the formula (8).

Specific examples of the monomer represented by the formula (11) are: methyl 2-(hydroxymethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate, isopropyl 2-(hydroxymethyl)acrylate, 2- (Hydroxymethyl) n-butyl acrylate, tert-butyl 2-(hydroxymethyl) acrylate. Among them, preferred are methyl 2-(hydroxymethyl)acrylate and ethyl 2-(hydroxymethyl)acrylate, and the best is obtained from the viewpoint of producing an optical film 1 having high transparency and heat resistance. It is methyl 2-(hydroxymethyl)acrylate (MHMA).

Further, the constituent unit formed by the polymerization of the monomers has a function of imparting positive intrinsic birefringence to the polymer having the unit by cyclization.

The monomer group used to form the polymer (a) may contain two or more kinds of monomers represented by the formula (11).

The monomer group used to form the polymer (a) may further contain a monomer other than the monomer represented by the formula (11). The monomer to be copolymerized with the monomer represented by the formula (11) is not particularly limited, and examples thereof include a (meth) acrylate other than the monomer represented by the formula (11).

The above (meth) acrylate is, for example, an acrylate such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, cyclohexyl acrylate or benzyl acrylate; Methyl acrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate A methacrylate such as an ester. Among them, methyl methacrylate (MMA) is preferred from the viewpoint of producing an optical film 1 having high transparency and heat resistance.

The monomer group used for forming the polymer (a) may contain two or more kinds of these (meth) acrylates.

The monomer group used for forming the polymer (a) may further contain one or two kinds of monomers such as styrene, vinyl toluene, α-methylstyrene, acrylonitrile, methyl ketene, ethylene, propylene, and vinyl acetate. More than one species.

The polymer (B-2) having the constituent unit Y can be formed by polymerizing a monomer group containing the above (meth) acrylate monomer and a monomer which becomes a unit Y by polymerization. By selecting the type of (meth) acrylate contained in the monomer group and cyclizing and condensing the formed polymer, the polymer (B-2) can have a constituent unit Y or a ring structure in the main chain. .

The polymer (B-1) is not particularly limited as long as it has a constituent unit Y and has a negative intrinsic birefringence.

The constituent unit Y has a function of greatly increasing the wavelength dispersibility of the birefringence in the polymer (B-1) having the unit in the main chain (refer to Table 6, Table 12, Table 16, and Table of the examples of the present application). 27). Therefore, by the combination of the polymers (B-1) and (B-2), the degree of freedom in control of the reverse wavelength dispersion can be improved. When the polymer (B-2) is a (meth)acrylic polymer, particularly in the case of a (meth)acrylic polymer having a lactone ring structure or a pentaneimine structure in the main chain (as described above, The polymer has a very small wavelength dispersion of birefringence, and the degree of freedom in controlling the reverse wavelength dispersion of the optical film 1 can be further improved.

Further, in the combination of the resins exemplified in Japanese Laid-Open Patent Publication No. 2001-337222, the wavelength dispersion of the birefringence of the two resins is not greatly different, and thus the optical film of the present invention cannot be obtained.

Since the constituent unit Y has a function of greatly increasing the wavelength dispersibility of the birefringence of the polymer (B-1), even when the ratio of the constituent unit Y to the total constituent unit of the polymer (B-1) is low, the polymerization is performed. The substance (B-1) also exhibits a large wavelength dispersion of birefringence. Further, a polymer which has been conventionally used for an optical member such as polycarbonate or polystyrene, even if it is a homopolymer, exhibits an approximate value of 0.95 in terms of the R/R0 value in the visible light region shown in this embodiment. Wavelength dispersion in the range of ~1.15 or so.

The reason why the constituent unit Y is capable of greatly increasing the wavelength dispersibility of the birefringence of the polymer is that the absorption spectrum state of the unit Y in the wavelength band of 300 to 450 nm is largely correlated.

The refractive index characteristics of the birefringent polymer are specifically caused by the anisotropy of the refractive index. The refractive index characteristics of the polymer are governed by the refractive index characteristics of the constituent units constituting the polymer. For example, when the polymer has two or more constituent units, the refractive index characteristics of the polymer are determined by the balance point of the refractive index characteristics of each constituent unit.

Here, the change in the refractive index characteristic of the constituent unit of the light of the specific wavelength band is considered to be related to the change in the absorption spectrum of the constituent unit of the light of the wavelength band. Specifically, when the change in the absorption spectrum of the constituent unit in a specific wavelength band is large, the change in the refractive index characteristic of the constituent unit in the wavelength band becomes large, and the wavelength dispersion of the birefringence of the constituent unit increases. Big. This phenomenon can be derived by the following formula: (1) shows the relationship between the refractive index n and the specific permittivity εe of the substance representing the refractive index, n ² = εe (this equation is based on Maxwell's electromagnetic equation The relationship between the derived wave equation of the electromagnetic wave), (2) the relationship between the permittivity εe and the electromagnetic susceptibility χ (εe=1+χ), and (3) the electromagnetic susceptibility χ is χ=P/ε _o E (P: polarization, E: electric field, ε _o : vacuum permittivity), the polarization P is defined by the dipole moment per unit volume, the square of the dipole moment and the oscillator strength. Proportional, and the integral absorption coefficient of the sum of the oscillator intensity and the molar absorptivity is proportional.

However, the reverse wavelength dispersion is at least in the visible light region (a wavelength band of about 380 to 750 nm), and the shorter the wavelength of light, the smaller the birefringence. That is, the wavelength dispersion of the birefringence in the constituent unit is large, which means that the change in the refractive index characteristic of the constituent unit in the visible light region is also large.

The constituent unit of the polymer generally has an absorption peak in the ultraviolet region. There is an absorption peak at a distance away from the visible light region, and is not affected by the absorption peak in the visible light region, and the absorption spectrum of the constituent unit is hardly changed. That is, in this case, the refractive index characteristic of the constituent unit in the visible light region is hardly changed, and the change in the refractive index characteristic of the polymer including the unit becomes small, and the wavelength dispersion of the birefringence becomes small. On the other hand, even in the vicinity of the visible light region or in the visible light region, there is an absorption peak in a region of very short wavelength, since the side edge of the absorption peak falls into the visible light region, the absorption spectrum of the constituent unit will There is a big change in the visible light region. That is, in this case, the refractive index characteristic of the constituent unit in the visible light region greatly changes, and the change in the refractive index characteristic of the polymer including the unit becomes large, and the wavelength dispersion of the birefringence becomes large.

The state of the absorption spectrum of the unit in the wavelength band of 300 to 450 nm has a large influence on the change in the refractive index characteristics of the constituent units in the visible light region as described above. Specifically, the maximum absorption peak of the absorption spectrum in the visible light region of 450 nm or more must be absent, but if the maximum value of the Mohr absorption coefficient in the wavelength band of 300 to 450 nm is a certain value or more, The constituent unit of the absorption spectrum is considered to greatly increase the wavelength dispersion of the birefringence of the polymer including the unit (wherein the maximum value of the Mohr absorption coefficient, specifically, preferably the value of the degree or more is a future study) matter).

The maximum value of the absorption spectrum of the constituent unit in the wavelength band of 300 to 450 nm can be measured by using an ultraviolet-visible spectrophotometer to measure the ultraviolet-visible absorption spectrum of the polymer composed of the constituent unit, or by using a molecular orbital method. The unit or the monomer of the constituent unit obtained by polymerization is obtained by predictive calculation.

Molecular orbital method for the molar absorption coefficient of vinyl carbazole units, vinyl onion units and diphenyl fulven units (vinyl carbazole, vinyl onion, diphenyl fulvene) The prediction calculation results in the absorption peak of the absorption spectrum in the visible region of the visible light region above 450 nm regardless of the monomer, and the maximum value of the molar absorption coefficient in the wavelength band of 300-450 nm is 3000 L/(mol ‧ cm) or more. Further, the same calculation was carried out for styrene which is a constituent unit which hardly increases the wavelength dispersibility of the birefringence of the polymer, and as a result, the maximum value of the molar absorption coefficient in the wavelength band of 300 to 450 nm is 100 L/(mol ‧ cm) or less.

Further, the prediction calculation is performed in the following order. Initially, a single system for the object was made into a model compound using a molding device of a software Materials studio manufactured by Accelrys Software Inc., and a density-general function molecular orbital calculation software DMol3 was used to explore the most stable structure. When exploring the most stable structure, GGA/BLPY is used as a function to calculate the condition. Next, using the resulting most stable structure, the calculation of the ultraviolet-visible absorption spectrum was performed by the semi-empirical molecular orbital calculation software. The calculation of the spectrum was carried out by using VAMP manufactured by Accelrys Software Inc. in software and ZINDO/INDO/l in a Hamiltonian function.

A wave that greatly increases the birefringence of a polymer by constituting the unit Y The above description of the reason for the long dispersion is considered to be applicable to the molecular structure X having the same molecular structure.

The aromatic ring system increases the photoelastic coefficient of the polymer containing the ring. Therefore, in order to obtain an optical film excellent in optical characteristics, particularly an optical film suitable for an image display device, it is preferred to reduce the content of the aromatic ring in the film as much as possible. The polymer (B-1) having the unit Y has a large wavelength dispersibility even if the content of the constituent unit Y in the polymer is small, so that the aromatic ring in the polymer (B-1) can be suppressed on the one hand. The content is obtained, and an optical film having a higher degree of freedom in controlling the reverse wavelength dispersion is obtained. In other words, the optical film of the present invention containing the constituent unit Y (molecular structure X) has excellent optical characteristics with respect to birefringence and suppresses an increase in the photoelastic coefficient. Therefore, the film is suitably used in an image display device.

Further, since the constituent unit Y represented by the formula (4) does not contain an aromatic ring, the increase in the photoelastic coefficient in the optical film can be further suppressed by the polymer (B-1) having the constituent unit Y. In addition, the effect of suppressing the increase in the photoelastic coefficient of the optical film by constituting the unit Y (molecular structure X) is also the same in the optical films 11, 23, and 31 shown in the second embodiment.

When the polymer (B-1) has a negative intrinsic birefringence, it may contain a constituent unit other than the constituent unit Y. That is, the polymer (B-1) may be a copolymer of a monomer constituting the unit Y and another monomer by polymerization. In this case, the content of the constituent unit Y in the polymer (B-1) is preferably 20% by weight or more, and more preferably 30% by weight or more.

For example, the polymer (B-1) may have a constituent unit Y and a (meth) acrylate unit as a constituent unit. In this case, the compatibility with the polymer (B-2) of the (meth) acrylate polymer is improved, and the optical film 1 excellent in transparency is obtained.

The polymer (B-1) may have the above ring structure in the main chain. In this case, it becomes an optical film 1 which is excellent in heat resistance.

In a specific example, the polymer (B-1) may also have a constituent unit formed by polymerization of the following monomers: acrylic acid, methacrylic acid, alkyl acrylate (for example, methyl acrylate, ethyl acrylate, yttrium acrylate) Ethyl amide), alkyl methacrylate (such as methyl methacrylate, ethyl methacrylate, carbazole ethyl methacrylate), aminoalkyl acrylate (such as diethylamine ethyl acrylate), Aminoalkyl methacrylate, monoester of acrylic acid and diol, monoester of methacrylic acid and diol (such as hydroxyethyl methacrylate), alkali metal acrylate, alkali metal methacrylate, Ammonium acrylate, ammonium methacrylate, quaternary ammonium derivative of aminoalkyl acrylate, quaternary ammonium compound of diethylamine acrylate and methyl sulphate, vinyl methyl ether, vinyl ether, Alkali metal salt of ethylenesulfonic acid, ammonium salt of ethylenesulfonic acid, styrenesulfonic acid, styrenesulfonate, propylenesulfonic acid, propylenesulfonate, methacrylic acid, methacrylic acid sulfonate, vinyl acetate Ester, ethylene stearate, N-ethylene acetamide N-vinylformamide, acrylamide, methacrylamide, N-alkyl acrylamide, N-methylcellulose acrylamide, N,N-methylenebisacrylamide, diacrylate diol Ester, glycol dimethacrylate, divinyl phenyl ester, diol dipropylene ether.

The polymer (B-1) may have water solubility depending on the type of the constituent unit Y (more specifically, the type of the constituent unit represented by the formula (4)).

When the polymer (B-1) is water-insoluble, the weight average molecular weight thereof is, for example, 50,000 to 1,500,000, preferably 80,000 to 1,200,000, more preferably 100,000 to 900,000.

When the polymer (B-1) is water-soluble, the k value of the molecular weight index is, for example, 10 to 120, preferably 25 to 95, more preferably 30 to 85. The k value is a value measured by the Fikentscher method.

The method for producing the polymer (B-1) is not particularly limited, and it can be produced by a known method. For example, a monomer group containing a monomer which constitutes a unit Y by polymerization can be polymerized by a known method.

The monomer which is a unit Y by polymerization is, for example, a monomer represented by the following formulas (12) to (15).

The monomer represented by the formula (12) is ethylene decylamine, n is a natural number in the range of 1 to 4, and R ¹ and R ² are each independently a hydrogen atom or a methyl group.

The monomer represented by the formula (13) is a vinyl onion, the monomer represented by the formula (14) is diphenylfulvene, and the unit represented by the formula (15) is a vinyl carbazole. A monomer represented by the formula (12), (13), or (15) which has a polymerizable group-bonded vinyl group on the molecular structure X. A monomer represented by the formula (14) which has a methylene group of a polymerizable group bonded to the molecular structure X.

In the polymerization of the polymer (B-1), it is preferred to use at least one selected from the group consisting of a mixture of hydrogen peroxide and a metal salt, an azo compound, and an organic peroxide as a polymerization initiator.

An azo compound such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylisobutyronitrile), 2,2'-azobis (2,4) - dimethyl valeronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyrate) dimethyl ester , 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[N-( 2-carboxyethyl)-2-methylpropionamidine hydrate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'- Azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate, 1,1'-azobis(cyclohexane-1-carbonitrile). As the polymerization initiator, two or more kinds of azo compounds may be used in combination.

Among these azo compounds, 2,2'-azobis(2-methylisobutyronitrile), 2,2'-azobis(isobutyrate) dimethyl ester, 2,2' are preferred. - azobis(2-methylpropionamidine) dihydrochloride.

Organic peroxides such as benzammonium peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,1'-di -peroxy hydrazine tert-butyl-3,3,5-trimethylenecyclohexane, 1,3-di-(t-butylperoxy)-diisopropylbenzene, peroxide-third Butyl ester, butyl tertiary oxyperoxide, ethyl butyl t-butyl-2-hexanoate, tert-butyl peroxy isobutyrate, ethyl peroxylated pentyl-2-hexanoate Oxidation of the third ester of hydroxy. Two or more types of organic peroxides may be used in combination with the polymerization initiator.

Among the organic peroxides, preferred are hydroxybutyl butyl peroxide and ethyl pentyl-2-hexanoate peroxide, and most preferred is ethyl pentyl-2-hexanoate peroxide. .

The concentration of the polymerization initiator in the polymerization system of the polymer (B-1) is not particularly limited as long as it is adjusted depending on the type and concentration of the monomer to be polymerized, and is, for example, 0.001 by weight based on 100 parts by weight of the monomer. It is preferably from 5,000 parts by weight to 2 parts by weight, preferably from 5,000 parts by weight to 2 parts by weight.

In the polymerization system, a chain transfer agent, a pH adjuster, a buffer material, or the like may be added as needed.

The polymerization solvent is not particularly limited, and examples thereof include a ketone-containing solvent (such as a mixed solvent of acetone and toluene), an ester solvent (such as ethyl acetate or butyl acetate), and a mixed solvent thereof. When the water-soluble polymer (B-1) is polymerized, water or a lower alcohol (methanol, ethanol, isopropanol, diethylene glycol, or the like) may be used as the polymerization solvent.

The polymerization temperature is not particularly limited as long as it is adjusted depending on the type of the monomer to be polymerized, and is, for example, 40 ° C to 100 ° C, preferably 50 ° C to 95 ° C, and more preferably 60 ° C to 90 ° C.

The mixing ratio of the polymer (B-1) to the polymer (B-2) in the resin (A) is determined by the absolute value of the intrinsic birefringence of each polymer or the desired reverse wavelength dispersion of the optical film 1. The degree may vary, and thus cannot be generalized. For example, the weight ratio may be (B-1): (B-2) = 1:99 to 99:1, preferably (B-1): (B- 2) = 10: 90 to 90: 10, more preferably (B-1): (B-2) = 20: 80 to 80: 20. Within this range, the degree of freedom in controlling the reverse wavelength dispersion can be improved, and it can be used as the optical film 1 having good reverse wavelength dispersion for the intended use.

The resin (A) in the present embodiment may contain two or more kinds of polymers (B-1) or two or more kinds of polymers (B-2).

When the polymer (B-2) is a (meth)acrylic polymer, the total content of the (meth)acrylic polymer in the resin (A) is preferably 50% by weight or more.

In the resin (A) of the present embodiment, if an optical film exhibiting reverse wavelength dispersibility can be obtained, it may contain any polymer other than the polymers (B-1) and (B-2).

The constituent unit Y shows very strong hygroscopicity depending on the type thereof. Therefore, the resin (A) has a composition unit Y type of the polymer (B-1), a content ratio of the constituent unit Y in the polymer (B-1), and a polymer (B-1) in the resin (A). The content rate of the ) sometimes makes it difficult to form a layer separately. In this case, the resin (A) may contain a polymer (adhesive polymer) which is a binder having a polymer (B-1) constituting the unit Y. Further, the binder polymer preferably has an intrinsic birefringence approaching zero, that is, a polymer which is stretched to exhibit almost no birefringence, and at this time, control of optical characteristics of the optical film 1 becomes easy. .

When the resin (A) contains a binder polymer, for example, the weight ratio may be (B-1): binder polymer = 10:90 to 70:30, preferably (B-1): binder polymer =20:80~60:40 range.

The content ratio of the polymer contained in the resin (A) and the content ratio of the constituent units in the polymer can be determined by a known method such as ¹ H nuclear magnetic resonance ( ¹ H-NMR) or infrared spectroscopic analysis (IR).

The optical film 1 may have any layer other than the layer 2 as needed.

The method for producing the optical film 1 is not particularly limited, and may be a known method. For example, the resin (A) containing the polymers (B-1) and (B-2) is formed into a film, and then the obtained film is stretched in a predetermined direction (typically, one-axis stretching or sequential biaxial stretching). The molecular chain of the polymer contained in the resin (A) is aligned to form the layer 2, and the optical film 1 may be used.

The resin (A) can be formed into a film by a known method such as a casting method or a melt molding method (for example, melt extrusion molding or press molding).

(Embodiment 2)

Fig. 2 shows another example of the optical film of the present invention. The optical film 11 shown in Fig. 2 is composed of a single layer 12 composed of a resin (A) containing a polymer (B-1) having a constituent unit Y. In the present embodiment, the polymer (B-1) has a constituent unit Y (which is a constituent unit having a function of imparting a negative intrinsic birefringence to the polymer), and further has a constituent unit Z (which has the polymer) Give positive intrinsic birefringence). The polymer (B-1) of the present embodiment is hereinafter described as a polymer (B-3).

When the polymer (B-3) is subjected to alignment, the birefringence derived from each of the constituent units Y and Z cancels each other. Here, the degree of birefringence cancellation varies with wavelength, so birefringence, such as reverse wavelength dispersion of phase difference, occurs.

The optical film 11 shows the reverse wavelength dispersion of a single layer. Therefore, it is possible to obtain desired optical characteristics while thinning, and it is possible to further reduce the size and weight of the image display device including the optical film 11. Further, the optical film 11 has higher productivity than the optical film which realizes reverse wavelength dispersion by laminating a plurality of layers, since it is not necessary to adjust the bonding angle of each layer.

When focusing on the alignment of the polymer (B-3), the optical film 11 is a member in which the resin (A) containing the polymer (B-3) is imparted with an alignment. As for the orientation of the resin (A), the formed resin (A) may be stretched into a film.

The polymer (B-3) is not particularly limited as long as it has the constituent units Y and Z.

The constituent unit Z is not particularly limited as long as it has a function of imparting positive intrinsic birefringence to the polymer (B-3). The constituent unit Z is, for example, at least one selected from the group consisting of a (meth) acrylate unit, a (meth) acrylate unit derivative ring structure, and a cycloolefin unit. The constituent unit Z is preferably at least one selected from the group consisting of a (meth) acrylate unit and a derivative of the unit. In this case, the degree of freedom in controlling the reverse wavelength dispersion in the optical film 11 is improved.

The constituent unit Y has a strong effect of increasing the wavelength dispersion of birefringence in the polymer (B-3). On the other hand, the ring structure of the (meth) acrylate unit and the derivative of the unit is not strong enough to increase the wavelength dispersibility of the birefringence in the polymer (B-3). As described above, the degree of wavelength dispersion of the polymer (B-3) is increased to increase the degree of freedom in controlling the reverse wavelength dispersion by combining different constituent units.

Further, in the combination of molecular chains disclosed in Japanese Laid-Open Patent Publication No. 2001-235622, since the difference in wavelength dispersibility between the two is not large, it is not possible to obtain a polymer (B-3) having a constituent unit Y. The effect of the optical film of the present invention.

The ring structure is, for example, a ring structure exemplified as the polymer (B-2) in the first embodiment.

When the total amount of the (meth) acrylate unit and the ring structure in the polymer (B-3) is 50% by weight or more, the polymer (B-3) is regarded as a (meth) acrylate polymer. . In this case, the optical film 11 having excellent optical properties, mechanical strength, moldability, and surface hardness is obtained.

The polymer (B-3) preferably has both a (meth) acrylate unit and a ring structure as a constituent unit Z. That is, the polymer (B-3) is preferably a (meth)acrylic polymer having a ring structure in the main chain. The constituent unit containing the ring structure has a function of imparting a large positive intrinsic birefringence at the time of alignment with respect to the polymer (B-3) having the unit. Therefore, by combining the constituent units Y, the degree of freedom in the control of the reverse wavelength dispersion in the optical film 11 can be improved.

In addition, when the polymer (B-3) has a ring structure in the main chain, the polymer (B-3) and the Tg of the resin (A) containing the polymer increase, and the optical film 11 having high heat resistance is obtained.

The polymer (B-3) having a ring structure in the main chain and the Tg of the resin (A) containing the polymer are, for example, 110 ° C or higher. The Tg is 115° C. or higher, 120° C. or higher, and further 130° C. depending on the type of the ring structure, the content of the ring structure in the polymer (B-3), and the content of the polymer (B-3) in the resin (A). the above.

The ring structure is as described in the first embodiment, and is preferably at least one selected from the group consisting of a lactone ring structure and a glutarimide structure, and more preferably a lactone ring structure. These ring structures have a function of imparting positive intrinsic birefringence to the polymer (B-3), but their wavelength dispersion is extremely small. Therefore, by combining the constituent units Y, the degree of freedom in the control of the reverse wavelength dispersion in the optical film 11 can be further improved.

The constituent unit Y is not particularly limited, and is preferably a unit or an unsaturated monomer unit represented by the formula (4). In other words, the polymer (B-3) preferably has a unit or an unsaturated monomer unit represented by the formula (4) as a constituent unit having a negative intrinsic birefringence imparting a negative effect on the polymer.

The polymer (B-3) may also be a random copolymer which is randomly disposed in the main chain with constituent units Y and Z, or may be a block copolymer having a block composed of constituent units Y and It constitutes the block formed by unit Z. Further, it may be a graft copolymer in which a side chain having another constituent unit (for example, a constituent unit Z) is bonded to a main chain having a constituent unit (for example, a constituent unit Y) selected from one of constituent units Y and Z. .

The polymer (B-3) may have two or more constituent units Y.

The polymer (B-3) may have any constituent unit other than the unit Y and Z if an optical film exhibiting reverse wavelength dispersibility can be obtained.

The polymer (B-3) can be produced by a known method.

The ratio of the content ratio of the constituent units Y and Z in the polymer (B-3) depends on the degree of action of each constituent unit on the intrinsic birefringence of the polymer (B-3) or the desired reverse wavelength dispersion of the optical film 11. The degree of the property is different, and the like cannot be generalized. For example, in terms of the weight ratio, the constituent unit Y is in the range of the constituent unit Z=1:99 to 38:62. Within this range, the degree of freedom of control of the reverse wavelength dispersion can be improved, and an optical film 11 having good reverse wavelength dispersion for the purpose of use can be obtained.

The content of the polymer (B-3) in the resin (A) is not particularly limited, and is usually 50% by weight or more, preferably 60% by weight or more, more preferably from the viewpoint of obtaining the effect of the present invention. It is 70% by weight or more.

The resin (A) of the present embodiment may contain two or more kinds of polymers (B-3).

The optical film 11 may have any layer other than the layer 12 as needed.

The method for producing the optical film 11 is not particularly limited, and may be a known method. For example, the resin (B) containing the polymer (B-3) is formed into a film, and then the obtained film is stretched in a predetermined direction (typically, one-axis stretching or sequential biaxial stretching), so that the resin (A) The molecular chain of the contained polymer is aligned to form the layer 12, and it can be used as the optical film 11.

The resin (A) can be formed into a film by a known method such as a casting method or a melt molding method (for example, melt extrusion molding or press molding).

(Embodiment 3)

Fig. 3 shows another example of the optical film of the present invention. The optical film 21 shown in Fig. 3 has a structure in which a double layer 22, 23 is laminated. The layer 22 is composed of a resin (A) containing a polymer (B-1) having a constituent unit Y, and the intrinsic birefringence of the resin (A) is a negative value. Layer 23 is composed of a resin (C) having positive intrinsic birefringence.

The optical film 21 has a structure in which two types of layers (layers 22 and 23) having different intrinsic birefringence layers are laminated. However, in the laminated structure, birefringence of two layers causes a phenomenon in which incident light cancels each other. Here, the degree of birefringence cancellation varies depending on the wavelength, so the optical film 21 exhibits reverse wavelength dispersion.

Further, in the optical film 21, the layer 22 and the layer 23 are independently disposed, since it is not necessary to consider the compatibility between the polymers having different sign of the inherent birefringence, or the sign of the inherent birefringence imparted to the polymer. The compatibility between the constituent units is such that the layers can take a wide range of compositions. Thereby, it is possible to become an optical member having a degree of freedom in controlling the reverse wavelength dispersion to a degree of freedom in optical design.

Layers 22, 23 produce birefringence by the alignment of the polymers contained in the layer. From this point of view, the layer 22 is a layer formed by aligning the resin (A), and the layer 23 is a layer formed by aligning the resin (C). As for the method of imparting the alignment of the resins (A) and (C), the resin (A) or (C) forming the film may be stretched.

The resin (C) is not particularly limited as long as it has positive intrinsic birefringence, and for example, it may contain a polymer having positive intrinsic birefringence. As an example of the polymer having positive intrinsic birefringence, it may be the above polymer (B-2).

The polymer (B-2) is preferably a (meth)acrylic polymer, and in this case, the degree of freedom in controlling the reverse wavelength dispersion in the optical film 21 can be improved. Although the layer 22 is composed of the resin (A) having the polymer (B-1), the layer exhibits a wavelength dispersion of birefringence as compared with a polymer containing a (meth)acrylic polymer (B). The layer 23 composed of the resin (C) of -2) exhibits a much larger wavelength dispersion of birefringence. As described above, the degree of freedom in the control of the reverse wavelength dispersion in the optical film 21 can be improved by combining two types of independent layers in which the wavelength dispersion of birefringence is completely different.

Further, the layers 22 and 23 formed by the combination of the resins exemplified in Japanese Laid-Open Patent Publication No. 2001-337222 (for example, the layer 23 is formed using polydecazene, and the layer is formed using a styrene polymer. 22), since the difference in wavelength dispersibility of the birefringence exhibited by each layer is not large, the layer 23 composed of the resin (C) of the polymer (B-2) containing the (meth)acrylic polymer cannot be obtained. The effect when combined with the layer 22 composed of the resin (A) having the polymer (B-1).

The polymer (B-2) is preferably a (meth)acrylic polymer having a ring structure in the main chain. Since the polymer (B-2) has a ring structure in the main chain, the absolute value of the intrinsic birefringence of the layer 23 becomes large. Therefore, by combining the layers 22, the degree of freedom in the control of the reverse wavelength dispersion in the optical film 21 can be improved.

Further, as described in the first embodiment, since the polymer (B-2) has a ring structure in the main chain, the Tg of the polymer (B-2) and the resin (C) containing the polymer rises, and the layer 23 and The heat resistance of the optical film 21 rises. The degree of increase in Tg by the ring structure is as described above.

The ring structure is preferably at least one selected from the group consisting of a lactone ring and a pentylene imine structure, as described in Embodiment 1, and more preferably a lactone ring structure. These ring structures have a function of imparting positive intrinsic birefringence to the polymer (B-2), but their wavelength dispersion is extremely small. Therefore, by combining the layer 22 containing the polymer (B-1), the degree of freedom in controlling the reverse wavelength dispersion in the optical film 21 can be further improved.

Other preferable conditions of the polymer (B-2) are the same as those of the polymer (B-2) described in the first embodiment.

The resin (C) containing the polymer (B-2) may contain a polymer other than the polymer (B-2) if it has a positive intrinsic birefringence.

The polymer (B-1) in the present embodiment is the same as the polymer (B-1) described in the first embodiment.

The resin (A) in the present embodiment is not particularly limited as long as it contains a polymer (B-1) having a constituent unit Y and has a negative intrinsic birefringence. For example, a polymer other than the polymer (B-1) may be contained. .

Further, the constituent unit Y shows very strong hygroscopicity depending on the kind thereof. Therefore, the polymer (B-1) may not easily form a layer separately depending on the type of the constituent unit Y of the polymer and the content ratio of the constituent unit Y in the polymer. In this case, the resin (A) may contain a polymer (adhesive polymer) which is a binder of the polymer (B-1). The binder polymer preferably has an intrinsic birefringence approaching zero, that is, a polymer which is stretched to exhibit little birefringence, and control of the optical properties of the layer 22 becomes easy.

The method for producing the optical film 21 is not particularly limited. As an example of the formation method, there is a method of joining the layers 22 and 23 which are separately formed. For example, the resin (A) containing the polymer (B-1) is formed into a film, and then the resulting film is stretched in a predetermined direction (typically, one-axis stretching or sequential biaxial stretching), so that the resin (A) The molecular chains of the contained polymers are aligned to form layer 22. In addition, the resin (C) containing the polymer (B-2) is also formed into a film, and then the obtained film is stretched in a predetermined direction so that the molecular chain of the polymer contained in the resin (C) is aligned. The layer 23 is formed. Next, the layers formed of the two are laminated to form the optical film 21 shown in FIG. The bonding of the layer 22 and the layer 23 may be carried out in accordance with a known method, or the layers of the two layers may be bonded to each other by an acrylic adhesive or the like. The resins (A) and (C) can be formed into a film by a known method such as a casting method or a melt molding method (for example, melt extrusion molding or press molding).

As another example of the formation method, a pre-stretch film (an unstretched film or a tentative stretched film) which is a precursor of the layer 22 and a pre-stretch film which is a precursor of the layer 23 are formed. The method in which the laminate is stretched in a predetermined direction. By this stretching, the molecular chains of the polymers (B-1) and (B-2) contained in the respective precursors are aligned to form an optical film 21 of the laminate formed by the layers 22 and 23. The laminate of the precursor may also be formed by laminating, for example, a film composed of the resin (A) and a film composed of the resin (C), or by coextruding the resin (A) with the resin (C). Formed to form. Further, a solution in which a resin which is a precursor of another layer is dissolved may be applied to a film of one of the layers 22 or 23, and the coating film may be dried. In a specific example, a solution containing a polymer (B-1) having a constituent unit Y is coated on a base film made of a (meth)acrylic polymer, a cycloolefin polymer or a cellulose derivative. The method of drying the whole and then stretching the obtained laminate in a predetermined direction.

The laminated state of the layers 22 and 23 (for example, the laminated pattern of the layers 22 and 23 or the inclination angle between the alignment axis of the layer 22 and the alignment axis of the layer 23 due to the vertical direction of the surface of the optical film 21) is not particularly limited. It can be appropriately selected in conjunction with optical design matters. Further, when the layers 22 and 23 are laminated in such a manner that their respective stretching directions are approximately uniform, the optical film 21 exhibits the strongest reverse wavelength dispersion.

The number of layers 22 and 23 having the optical film 21 is not particularly limited. In addition, layer 22 and layer 23 may or may not be in contact.

The optical film 21 may have layers other than the layers 22 and 23 as needed.

(Embodiment 4)

Fig. 4 shows another example of the optical film of the present invention. The optical film 31 shown in Fig. 4 is composed of a single layer 32 composed of a resin (A) containing a polymer (B-4) having a molecular structure X-modified constituent unit.

When the polymer (B-4) is subjected to alignment, the degree of modification of the molecular structure X varies depending on the constituent units, and thus the birefringence generated from each constituent unit cancels each other. Here, the degree of birefringence cancellation varies with wavelength, so birefringence, such as reverse wavelength dispersion of phase difference, occurs.

The polymer (B-4) can be formed by a known method. For example, a compound in which a binding group capable of binding to a constituent unit of a modified object is bonded to the molecular structure X may be reacted with a polymer having the constituent unit. When the polymer is a cellulose derivative such as TAC, the binding group is, for example, a hydroxyl group. When the molecular structure X is a structure represented by the formula (1), the above compound is, for example, an oxychloride of 5-oxopyrrolidine-2-carboxylic acid. For the formation of oxychloride, sulfinium chloride can be used.

The optical film 31 may also have a layer other than the layer 32 as needed.

The method for producing the optical film 31 is not particularly limited, and may be a known method. For example, the resin (B) containing the polymer (B-4) is formed into a film, and then the obtained film is stretched in a predetermined direction (typically, one-axis stretching or sequential biaxial stretching), so that the resin (A) The molecular chain of the contained polymer is aligned to form the layer 32, and it can be used as the optical film 31.

The resin (A) can be formed into a film by a known method such as a casting method or a melt molding method (for example, melt extrusion molding or press molding).

(Use of optical film)

The optical film of the present invention exhibits reverse wavelength dispersion. That is, the optical film of the present invention exhibits optical characteristics that the shorter the wavelength, the smaller the birefringence (or the phase difference or the retardation path), at least in the visible light region. By using such a wide-spectrum optical film, an image display device excellent in display characteristics can be constructed.

The optical film of the present invention can be used as, for example, a phase difference plate, or a λ/4 plate which is one type of a phase difference plate, and can have a retardation optical path of a phase difference obtained as a quarter of a light wavelength. Further, the optical film of the present invention may be combined with other optical members such as a polarizing plate as an antireflection plate.

The optical film of the present invention may be a polarizing element protective film. In particular, for the reason described above, when the resin (A) has a molecular structure represented by the formula (1), it can be preferably used as a polarizing element protective film.

The optical film of the present invention can also be used in combination with other optical members depending on the application.

The use of the optical film of the present invention is not particularly limited, and can be used for the same applications as conventional optical members (for example, image display devices such as LCDs and OLEDs).

Example

The invention will now be described in more detail by way of examples. The invention is not limited to the embodiments shown below.

(Manufacturing Example 1)

15 parts by weight of methyl 2-(hydroxymethyl)acrylate (MHMA), 35 parts by weight of methyl methacrylate (MMA), and 50 parts by weight of toluene as a polymerization solvent, equipped with a stirring device, temperature In the reaction apparatus of the sensor, the cooling tube, and the nitrogen gas introduction tube, the temperature was raised to 105 ° C while nitrogen gas was supplied thereto. At the beginning of the reflux accompanied by the temperature rise, 0.03 parts by weight of the third isoammonium peroxydecanoate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 3.34 parts by weight. In the toluene, while 0.06 parts by weight of the above-mentioned third amyl isophthalate was dissolved, the solution polymerization was carried out under reflux at about 105 to 110 ° C, and then aging was carried out for 4 hours.

Next, 0.1 part by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for a cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Next, the polymerization solution obtained above was dried at 240 ° C for 1 hour under reduced pressure to form a transparent polymer (B-2A) having a lactone ring structure in the main chain.

(Manufacturing Example 2)

15 parts by weight of MHMA, 25 parts by weight of MMA, 10 parts by weight of benzyl methacrylate, and 50 parts by weight of toluene as a polymerization solvent, equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen gas In the reaction apparatus of the introduction tube, the temperature was raised to 105 ° C while introducing nitrogen gas. At the beginning of the reflux accompanied by the temperature rise, 0.03 parts by weight of the third isoammonium peroxydecanoate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 3.34 parts by weight. In the toluene, 0.06 parts by weight of the above-mentioned third isoammonium peroxydecanoate was added dropwise thereto over 6 hours, and solution polymerization was carried out under reflux at about 105 to 111 ° C, followed by aging for 2 hours.

Next, 0.1 part by weight of a octyl phosphate/dioctyl ester mixture as a cyclization catalyst was added to the obtained polymerization solution, followed by a cyclization condensation reaction at reflux of about 80 to 105 ° C for 2 hours.

Next, the polymerization solution obtained above was dried at 240 ° C for 1 hour under reduced pressure to form a transparent polymer (B-2B) having a lactone ring structure in its main chain.

(Manufacturing Example 3)

10 parts by weight of vinyl carbazole, 18 parts by weight of MHMA, 72 parts by weight of MMA, and 80 parts by weight of toluene as a polymerization solvent were charged into a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube. In the reaction apparatus, the temperature was raised to 105 ° C while introducing nitrogen gas. At the beginning of the reflux accompanied by the temperature rise, 0.1 part by weight of a third amyl peroxyisophthalate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 10 parts by weight. In the toluene, 0.2 part by weight of the above-mentioned third amyl peroxyisophthalate was added dropwise thereto over 2 hours, and solution polymerization was carried out under reflux at about 105 to 110 ° C, followed by aging for 4 hours.

Next, 0.9 parts by weight of an octyl phosphate/dioctyl ester mixture dissolved in 10 parts by weight of toluene was added to the obtained polymerization solution, and MHMA units in the polymer formed by the above polymerization were further refluxed for 2 hours. A cyclization condensation reaction is carried out between MMA units.

Next, the polymerization solution obtained above was dried at 240 ° C for 1 hour under reduced pressure to form a transparent polymer (B-1A) having a vinyl carbazole structure in its main chain. Further, the obtained polymer (B-1A) has a lactone ring structure in the main chain, and this lactone ring structure is promoted with a polymer (B-1A), a polymer (B-2A) or a polymer (B- The compatibility of 2B) is introduced as a purpose.

(Example 1)

10 parts by weight of the polymer (B-2A) obtained in Production Example 1 and 20 parts by weight of the polymer (B-1A) obtained in Production Example 3 were dissolved in methyl isobutyl ketone, and the obtained The solution was stirred to uniformly mix the polymer (B-2A) and the polymer (B-1A). Next, the obtained mixed solution was dried at 240 ° C for 1 hour under reduced pressure to obtain 30 parts by weight of a solid resin.

Next, the obtained resin was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 100 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 138 ° C by a biaxial stretching device (manufactured by Toyo Seiki Seisakusho Co., Ltd.) so that the stretching ratio in the MD direction was doubled, and the thickness was obtained. 40 μm stretch film.

The wavelength dispersion of the phase difference (phase difference in the film surface) and the alignment angle of the obtained stretched film were evaluated by using a fully automatic birefringence meter (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.), and the wavelength dispersion property was The evaluation results are shown in Table 1 below. In each of the tables of the first and subsequent examples and the comparative examples, the phase difference at the measurement wavelength of 590 nm is used as a reference (R0), and the ratio of the phase difference R of another wavelength to R0 (R/R0) is displayed together. ). Further, the in-plane phase difference shown in each table is a value at a film thickness of 100 μm.

As shown in Table 1, the stretched film obtained in Example 1 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

The oriented film (Φ) of the stretched film obtained in Example 1 was -0.8. , that is, its intrinsic birefringence is positive.

(Example 2)

A stretched film was obtained in the same manner as in Example 1 except that the polymer (B-2B) obtained in Production Example 2 was used instead of the polymer (B-2A), and the obtained stretched film was obtained. The wavelength dispersion of the phase difference and the alignment angle were also evaluated in the same manner as in the first embodiment. The evaluation results of the wavelength dispersibility are shown in Table 2 below.

As shown in Table 2, the stretched film obtained in Example 2 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

The stretched film obtained in Example 2 had an alignment angle (ψ) of 0.6°, that is, its intrinsic birefringence was positive.

(Example 3)

In place of the polymer (B-2A), and the polymer (B-1A) obtained in Production Example 3, except that 10 parts by weight of a propylene sulfimine polymer (KAMAX T-240, manufactured by Rohm and Haas Co., Ltd.) was used. 35 parts by weight of a solid resin was obtained in the same manner as in Example 1 except that the amount used was 25 parts by weight. Further, the acrylonitrile imine polymer to be used has a N-methyl-dimethylpentaneimine unit and a methacrylate unit as constituent units thereof as shown in the following formula (16).

Next, the obtained resin was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 100 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 143 ° C by a biaxial stretching apparatus so that the stretching ratio in the MD direction was doubled, and a stretched film having a thickness of 50 μm was obtained.

Next, the wavelength dispersibility and the alignment angle of the phase difference of the obtained stretched film were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 3 below.

As shown in Table 3, the stretched film obtained in Example 3 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

The stretched film obtained in Example 3 had an alignment angle (Φ) of -2.1°, that is, its intrinsic birefringence was a positive value.

(Comparative Example 1)

Using only the polymer (B-2A) formed in Production Example 1, a stretched film of the polymer (B-2A) was obtained by press molding and one-axis stretching in the same manner as in Example 1. The wavelength dispersibility and the alignment angle of the phase difference of the obtained stretched film were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 4 below.

As shown in Table 4, the stretched film obtained in Comparative Example 1 exhibited a wavelength dispersion in which the wavelength of light was shorter and the phase difference was larger, that is, it exhibited birefringence with a general polymer such as polycarbonate. The same wavelength dispersion of the components.

The stretched film obtained in Comparative Example 1 had an alignment angle (Φ) of -0.7°, that is, its intrinsic birefringence was a positive value.

(Comparative Example 2)

Using only the acrylonitrile imine polymer used in Production Example 3, a stretched film having a thickness of 50 μm was obtained by press forming and axial stretching in the same manner as in Example 1. The wavelength dispersibility and the alignment angle of the phase difference of the obtained stretched film were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 5 below.

As shown in Table 5, the stretched film obtained in Comparative Example 2 showed a wavelength dispersion in which the phase difference was larger as the wavelength of light was shorter.

The stretched film obtained in Comparative Example 2 had an alignment angle (Φ) of -0.8°, that is, its intrinsic birefringence was a positive value.

(Comparative Example 3)

Using only the polymer (B-1A) formed in Production Example 3, a stretched film of the polymer (B-1A) was obtained by press molding and one-axis stretching in the same manner as in Example 1. The wavelength dispersibility and the alignment angle of the phase difference of the obtained stretched film were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 6 below.

As shown in Table 6, the stretched film obtained in Comparative Example 3 exhibited a wavelength dispersion in which the wavelength of light was shorter and the phase difference was larger, but the dispersibility was comparable to that of a resin such as carbonate or polystyrene. Big.

The stretched film obtained in Comparative Example 3 had an alignment angle (Φ) of 89.4°, that is, its intrinsic birefringence was a negative value.

(Example 4)

The polymer (B-2A) obtained in Production Example 1 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 70 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 145 ° C by the above-described biaxial stretching device so that the stretching ratio in the MD direction was doubled, and a stretched film having a thickness of 50 μm was obtained (F1). ).

Except that the polymer (B-1A) obtained in Production Example 3 was used instead of the polymer (B-2A), a stretched film having a thickness of 100 μm (F2) was obtained in the same manner as above. ).

Next, the obtained stretched film (F1) was used as the first layer and the stretched film (F2) as the second layer, and the two films were laminated while aligning the stretching directions (stretching axes) of the respective films. The wavelength dispersion and the alignment angle of the phase difference (in-plane phase difference) in the stretched film laminate obtained by lamination were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 7 below.

As shown in Table 7, the stretched film obtained in Example 4 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

The stretched film obtained in Example 4 had an alignment angle (Φ) of -0.8°, that is, its intrinsic birefringence was a positive value.

(Example 5)

The polymer (B-2B) obtained in Production Example 2 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 70 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 138 ° C by the above-described biaxial stretching device so that the stretching ratio in the MD direction was doubled, and a stretched film having a thickness of 50 μm was obtained (F3). ).

In addition, the polymer (B-1A) obtained in Production Example 3 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 210 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 138 ° C by the above-described biaxial stretching device so that the stretching ratio in the MD direction was doubled, and a stretched film having a thickness of 150 μm was obtained (F4). ).

Next, the obtained stretched film (F3) was used as the first layer and the stretched film (F4) as the second layer, and the two films were laminated while aligning the stretching directions (stretching axes) of the respective films. The wavelength dispersion and the alignment angle of the phase difference (in-plane phase difference) in the stretched film laminate obtained by lamination were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 8 below.

As shown in Table 8, the stretched film obtained in Example 5 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

The stretched film obtained in Example 5 had an alignment angle (Φ) of 0.6°, that is, its intrinsic birefringence was a positive value.

(Example 6)

The acrylonitrile imide resin used in Production Example 3 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 70 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 143 ° C by the above-described biaxial stretching device so that the stretching ratio in the MD direction was doubled, and a stretched film having a thickness of 50 μm was obtained (F5). ).

In addition, the polymer (B-1A) obtained in Production Example 3 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 180 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 138 ° C by the above-described biaxial stretching device so that the stretching ratio in the MD direction was doubled, and a stretched film having a thickness of 125 μm was obtained (F6). ).

Next, the obtained stretched film (F5) is used as the second layer of the first layer and the stretched film (F6), and the two layers are aligned while stretching the stretching direction (stretching axis) of each film. The film is laminated. The wavelength dispersion and the alignment angle of the phase difference (in-plane phase difference) in the stretched film laminate obtained by lamination were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 9 below.

As shown in Table 9, the stretched film obtained in Example 6 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

The stretched film obtained in Example 6 had an alignment angle (Φ) of 0.3°, that is, its intrinsic birefringence was a positive value.

(Comparative Example 4)

The wavelength dispersion and the alignment angle of the phase difference (in-plane phase difference) in the stretched film (F1) obtained in Example 4 were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 10 below.

As shown in Table 10, the stretched film (F1) showed the wavelength dispersion of the shorter the phase difference (slight width) of the light.

The oriented film (Φ) of the stretched film (F1) was -0.7°, that is, its intrinsic birefringence was positive.

(Comparative Example 5)

The wavelength dispersion and the alignment angle of the phase difference (in-plane phase difference) in the stretched film (F3) obtained in Example 5 were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 11 below.

As shown in Table 11, the stretched film (F3) showed wavelength dispersion in which the phase difference was slightly larger as the wavelength of light was shorter.

The oriented film (Φ) of the stretched film (F3) was -0.7°, that is, its intrinsic birefringence was positive.

(Comparative Example 6)

The polymer (B-1A) obtained in Production Example 3 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 70 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 138 ° C using a biaxial stretching apparatus as described above so that the stretching ratio in the MD direction was doubled, and a stretched film (F7) having a thickness of 50 μm was obtained. .

The wavelength dispersion and the alignment angle of the phase difference (in-plane phase difference) in the stretched film (F7) were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 12 below.

As shown in Table 12, the stretched film (F7) showed a wavelength dispersion which is shorter as the wavelength of light is larger, but the dispersibility is considerably larger than that of a resin such as carbonate or polystyrene.

The oriented film (Φ) of the stretched film (F7) was 89.8°, that is, its intrinsic birefringence was negative.

(Comparative Example 7)

The acrylonitrile imide resin used in Example 3 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 140 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 143 ° C using a biaxial stretching apparatus as described above so that the stretching ratio in the MD direction was doubled, and a stretched film (F8) having a thickness of 100 μm was obtained. .

The wavelength dispersion and the alignment angle of the phase difference (in-plane phase difference) in the stretched film (F8) were evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 13 below.

As shown in Table 13, the stretched film (F8) showed a wavelength dispersion in which the phase difference was larger as the wavelength of light was shorter.

The oriented film (Φ) of the stretched film (F8) was -0.9°, that is, its intrinsic birefringence was positive.

(Manufacturing Example 4)

18 parts by weight of methyl 2-(hydroxymethyl)acrylate (MHMA), 72 parts by weight of methyl methacrylate (MMA), 10 parts by weight of vinylcarbazole, and 90 parts by weight of toluene as a polymerization solvent. The reactor was equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen gas introduction tube, and the temperature was raised to 105 ° C while passing nitrogen gas. At the beginning of the reflux accompanied by the temperature rise, 0.1 part by weight of a third amyl peroxyisophthalate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 10 parts by weight. In the toluene, 0.2 part by weight of the above-mentioned third amyl peroxyisophthalate was added dropwise thereto for 3 hours, and solution polymerization was carried out under reflux at about 105 to 110 ° C, followed by heating and aging for 3 hours. .

Next, 0.9 parts by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for a cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Then, after further heating at 240 ° C for 90 minutes in an autoclave, the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a structure having a vinyl carbazole unit as a constituent unit and a lactone ring structure in the main chain. Transparent polymer (B-1B).

(Manufacturing Example 5)

15 parts by weight of MHMA, 35 parts by weight of MMA, and 50 parts by weight of toluene as a polymerization solvent were placed in a reaction apparatus equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube. The temperature was raised to 105 ° C while passing nitrogen gas. At the beginning of the reflux accompanied by the temperature rise, 0.03 parts by weight of a third amyl peroxyisophthalate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 3.3 parts by weight. In the toluene, 0.06 parts by weight of the above-mentioned third isoammonium peroxydecanoate was added dropwise thereto over 2 hours, and solution polymerization was carried out under reflux at about 105 to 110 ° C, followed by heating and aging for 4 hours. .

Next, 0.1 part by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for a cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Subsequently, the mixture was further heated at 240 ° C for 90 minutes in an autoclave, and the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a transparent polymer (B-2C) having a lactone ring structure in its main chain.

(Manufacturing Example 6)

6 parts by weight of MHMA, 74 parts by weight of MMA, 20 parts by weight of vinylcarbazole, and 90 parts by weight of toluene as a polymerization solvent, were charged with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube. In the reaction apparatus, the temperature was raised to 105 ° C while introducing nitrogen gas. At the beginning of the reflux accompanied by the temperature rise, 0.1 part by weight of a third amyl peroxyisophthalate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 10 parts by weight. In the toluene, 0.2 part by weight of the above-mentioned third amyl peroxide isotanoate was added dropwise thereto for 4 hours, and solution polymerization was carried out under reflux at about 105 to 110 ° C, followed by heating and aging for 3 hours. .

Next, 0.9 parts by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for a cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Then, after further heating at 240 ° C for 90 minutes in an autoclave, the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a structure having a lactone unit as a constituent unit and a lactone ring structure in the main chain. Transparent polymer (B-1C).

(Example 7)

The polymer (B-1B) obtained in Production Example 4 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 70 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 142 ° C so that the stretching ratio was doubled by an autostereoscopic measuring instrument (manufactured by Shimadzu Corporation), and a stretched film having a thickness of 45 μm was obtained ( F9).

In addition, a dichloromethane solution (concentration: 15% by weight) of cellulose acetate propionate (manufactured by Aldrich Co., Ltd., Mn = 15000) was cast on a glass plate and dried to obtain a thickness of 70 μm. film. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 160 ° C by the above-described autostereoscopic plotter so that the stretching ratio was 1.8 times, and a stretched film (F10) having a thickness of 50 μm was obtained.

Next, one stretched film (F9) and two stretched films (F10) were laminated while being stretched in the direction of stretching (stretching axis) of each film so as to sandwich F9 by F10. The wavelength dispersion of the phase difference (in-plane phase difference) in the obtained stretched film laminate was evaluated in the same manner as in Example 1. The evaluation results of the wavelength dispersibility are shown in Table 14 below.

As shown in Table 14, the stretched film obtained in Example 7 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

(Comparative Example 8)

The wavelength dispersion of the phase difference (in-plane phase difference) of the stretched film (F10) obtained in Example 7 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 15 below.

As shown in Table 15, the stretched film (F10) showed the wavelength dispersion of the shorter the phase difference (slight width) of the light.

The alignment angle of the stretched film (F10) was evaluated by using a fully automatic birefringence meter (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.), and as a result, the phase angle (Φ) was 1.4°, that is, cellulose acetate propionate. The intrinsic birefringence of the ester is positive.

(Comparative Example 9)

The wavelength dispersion of the phase difference (in-plane phase difference) of the stretched film (F9) obtained in Example 7 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 16 below.

As shown in Table 16, the stretched film (F9) showed a wavelength dispersion in which the wavelength of light was shorter and the phase difference was larger, and the wavelength dispersion property was considerably large.

The alignment angle of the stretched film (F9) was evaluated by using a fully automatic birefringence meter (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.), and as a result, the phase angle (Φ) was -86.4°, that is, the polymer (B). The intrinsic birefringence of -1B) is a negative value.

(Example 8)

20 parts by weight of the polymer (B-1B) obtained in Production Example 4 and 10 parts by weight of the polymer (B-2C) obtained in Production Example 5 were dissolved in methyl isobutyl ketone, and all were added. Stir and mix evenly. Next, the obtained mixed solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a solid resin.

Next, the obtained resin was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 90 μm. Then, the obtained film was further stretched at any end by a stretching temperature of 143 ° C by an autostereograph to obtain a stretching ratio of 2 times, and a stretched film (F11) having a thickness of 49 μm was obtained.

The obtained film (F11) was evaluated for its wavelength dispersion in phase difference (in-plane phase difference) in the same manner as in Example 1. The evaluation results are shown in Table 17 below.

As shown in Table 17, the stretched film (F11) showed a reverse wavelength dispersion in which the phase difference was smaller as the wavelength of light was shorter, and the wavelength dispersion property was considerably larger.

(Example 9)

The polymer (B-2C) obtained in Production Example 5 was press-formed at 250 ° C by a press molding machine to obtain a film (F12) having a thickness of about 80 μm. Then, a toluene solution (concentration: 30% by weight) of the polymer (B-1C) obtained in Production Example 6 was uniformly applied to the obtained film (F12) by a bar coater #58. surface. Then, the whole was dried at 60 ° C for 1 hour and at 120 ° C for 15 minutes to obtain a laminate having a laminated structure of a film (F12) and a layer composed of the polymer (B-1C). Then, the obtained laminate was subjected to one-axis stretching at any stretching temperature of 142 ° C by the above-mentioned autostereoscopic plotter so that the stretching ratio was doubled, and a stretched product having a film (F12) was obtained. The laminate structure of the stretched product of the polymer (B-1C) was a stretched film (F13) having a thickness of 70 μm.

The obtained film (F13) was evaluated for the wavelength dispersion of the phase difference (in-plane phase difference) in the same manner as in Example 1. The evaluation results are shown in Table 18 below.

As shown in Table 18, the stretched film (F13) showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the wavelength dispersion property was considerably large.

In addition to the evaluation of the wavelength dispersion of the phase difference (in-plane phase difference) of the stretched film obtained by stretching the film (F12) in the same manner without applying the solution of the polymer (B-1C) As a result, it shows that the shorter the wavelength of light, the larger the phase difference is. Further, the alignment angle (Φ) is close to 0°, that is, the intrinsic birefringence of the polymer (B-2C) is a positive value.

Further, in the same manner as in the stretched film (F9) of Example 7, the stretched film composed of the polymer (B-1C) was obtained, and the result of evaluation of the wavelength dispersion of the phase difference (in-plane phase difference) was obtained. The shorter the wavelength of the light is, the larger the phase difference is, and the wavelength dispersion is particularly large. Further, the alignment angle (Φ) is close to -90°, that is, the intrinsic birefringence of the polymer (B-1C) is a negative value.

(Embodiment 10)

The polymer (B-1B) obtained in Production Example 4 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 70 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 142 ° C by the above-described autostereoscopic plotter so that the stretching ratio was doubled, and a stretched film (F14) having a thickness of 45 μm was obtained.

In addition, a cycloolefin polymer film (ZEONOR ZF14, manufactured by Zeon Co., Ltd.) was subjected to one-axis stretching at any stretching temperature of 142 ° C by the above-mentioned autostereograph, so that the stretching ratio was doubled. A stretched film (F15) having a thickness of 63 μm was obtained.

Next, the obtained stretched film (F14) was used as the first layer and the stretched film (F15) as the second layer, and the two films were laminated while aligning the stretching directions of the respective films. The wavelength dispersion of the phase difference (in-plane phase difference) in the stretched film laminate obtained by lamination was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 19 below.

As shown in Table 19, the laminate of the stretched film (F14) and (F15) showed a reverse wavelength dispersion in which the phase difference was smaller as the wavelength of light was shorter.

(Comparative Example 10)

The wavelength dispersion of the phase difference (in-plane phase difference) of the stretched film (F15) obtained in Example 10 was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 20 below.

As shown in Table 20, the stretched film (F15) showed the wavelength dispersion of the shorter the phase difference (micro-format) as the wavelength of light was shorter.

Further, the positive and negative intrinsic birefringence in the stretched film (F15) was evaluated by determining the alignment angle of the film, and as a result, it was a positive value.

(Manufacturing Example 7)

25 parts by weight of MHMA, 68 parts by weight of MMA, 7 parts by weight of vinylcarbazole, and 90 parts by weight of toluene as a polymerization solvent were charged into a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube. In the reaction apparatus, the temperature was raised to 105 ° C while introducing nitrogen gas. At the beginning of the reflux accompanied by the temperature rise, 0.04 parts by weight of the third isoammonium peroxydecanoate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 10 parts by weight. In the toluene, while 0.08 parts by weight of the above-mentioned third amyl isophthalate was dissolved, the solution polymerization was carried out under reflux at about 105 to 110 ° C, and then heating and aging were carried out for 4 hours. .

Next, 0.9 parts by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for a cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Next, after further heating at 240 ° C for 90 minutes in an autoclave, the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a composition having a vinyl carbazole unit as a negative intrinsic birefringence imparted to the polymer. The unit has a lactone ring structure as a transparent copolymer (B-3A) which is a constituent unit which imparts positive intrinsic birefringence to the polymer.

(Manufacturing Example 8)

25 parts by weight of MHMA, 72 parts by weight of MMA, 3 parts by weight of vinyl onion, and 90 parts by weight of toluene as a polymerization solvent were charged into a reaction equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube. In the apparatus, the temperature was raised to 105 ° C while introducing nitrogen gas. At the beginning of the reflux accompanied by the temperature rise, 0.04 parts by weight of the third isoammonium peroxydecanoate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 10 parts by weight. In the toluene, while 0.08 parts by weight of the above-mentioned third amyl isophthalate was dissolved, the solution polymerization was carried out under reflux at about 105 to 110 ° C, and then heating and aging were carried out for 4 hours. .

Next, 0.9 parts by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for a cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Next, after further heating at 240 ° C for 90 minutes in an autoclave, the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a constituent unit having a vinyl onion unit as a negative intrinsic birefringence imparted to the polymer. Further, it has a lactone ring structure as a transparent copolymer (B-3B) which is a constituent unit which imparts positive intrinsic birefringence to the polymer.

(Example 11)

The copolymer (B-3A) obtained in Production Example 7 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 190 μm. Then, the obtained film was subjected to any end-axis stretching at a stretching temperature of 148 ° C by the above-described autostereoscopic plotter so that the stretching ratio was doubled, and a stretched film having a thickness of 130 μm was obtained.

The wavelength dispersion of the phase difference of the obtained stretched film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 21 below.

As shown in Table 21, the stretched film obtained in Example 11 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

(Embodiment 12)

The copolymer (B-3B) obtained in Production Example 8 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 130 μm. Then, the obtained film was further stretched at any end by a stretching temperature of 148 ° C by the above-described autostereoscopic plotter so that the stretching ratio was doubled, and a stretched film having a thickness of 90 μm was obtained.

The wavelength dispersion of the phase difference of the obtained stretched film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 22 below.

As shown in Table 22, the stretched film obtained in Example 12 showed the reverse wavelength dispersion in which the phase difference was smaller as the wavelength of light was shorter.

(Manufacturing Example 9)

15 parts by weight of methyl 2-(hydroxymethyl)acrylate (MHMA), 35 parts by weight of methyl methacrylate (MMA), and 50 parts by weight of toluene as a polymerization solvent, equipped with a stirring device, temperature In the reaction apparatus of the sensor, the cooling tube, and the nitrogen gas introduction tube, the temperature was raised to 105 ° C while nitrogen gas was supplied thereto. At the beginning of the reflux accompanied by the temperature rise, 0.03 parts by weight of the third isoammonium peroxydecanoate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 3.34 parts by weight. In the toluene, while 0.06 parts by weight of the above-mentioned third amyl isophthalate was dissolved, the solution polymerization was carried out under reflux at about 105 to 110 ° C, and then aging was carried out for 4 hours.

Next, 0.1 part by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for a cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Subsequently, the mixture was further heated at 240 ° C for 90 minutes in an autoclave, and the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a transparent polymer (B-2D) having a lactone ring structure in its main chain.

(Manufacturing Example 10)

576 parts by weight of deionized water was placed in a reaction apparatus equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube, and the temperature was raised to 80 ° C while introducing nitrogen gas. When the temperature in the reaction apparatus was stably maintained at 80 ° C, 534 parts by weight of N-vinyl-2-pyrrolidone was added dropwise to the reaction apparatus over 3 hours, and dissolved in 75.8 parts by weight of deionized as a polymerization initiator. A solution of 2.45 parts by weight of 2,2'-azobis(2-methylpropionamidine) dihydrochloride of water. After completion of the titration, the reaction was carried out for 4 hours while maintaining the temperature at 80 ° C, and then the obtained polymerization solution was dried at 150 ° C for 2 hours under reduced pressure to obtain a polymer (B-1D) of N-vinyl-2-pyrrolidone. The K value of the obtained polymer was 59.8. Here, the K value means a viscosity characteristic value relating to the molecular weight of the polymer, which is a value measured by the Fresnel method.

The method for measuring the K value obtained by the Faken method is as follows. Initially, 1.0 g of the polymer to be measured was dissolved in distilled water at room temperature to obtain a solution having a volume of 100 ml. Next, the obtained solution was placed in a thermostat kept at 25 ° C ± 0.2 ° C for 30 minutes, and the relative viscosity [η] of the solution was determined using a Ubbelohde viscometer. When the relative viscosity is determined, distilled water is used as the standard solution, and the flow time measured by the viscosity meter for the above solution and distilled water is corrected by the correction of Hagenbach-Couette. The relative viscosity [η] can be obtained from the flow time t1 of the above solution and the flow time t2 of the distilled water by the formula [η] = t1/t2. The K value can be obtained from the relative viscosity [η] obtained above and the concentration C of the solution (g/100 ml) by the following formula:

K value={{300C‧log[η]+(C+1.5C‧log[η]) ² } ^1/2 +1.5C‧log[η]-C}/(0.15C+0.003C ² )

If the K value measured by this method is less than 20, the concentration of the solution is set to 5.0 (g/100 ml) and then measured.

(Manufacturing Example 11)

The polymer (B-1D) of N-vinyl-2-pyrrolidone obtained in Production Example 10 was highly hygroscopic, and it was difficult to form a layer alone. Therefore, in Production Example 11, the bonding of the polymer was carried out in the following manner. The polymer of the agent.

10 parts by weight of methyl 2-(hydroxymethyl)acrylate (MHMA), 40 parts by weight of methyl methacrylate (MMA), and 50 parts by weight of toluene as a polymerization solvent, equipped with a stirring device, temperature In the reaction apparatus of the sensor, the cooling tube, and the nitrogen gas introduction tube, the temperature was raised to 105 ° C while nitrogen gas was supplied thereto. At the beginning of the reflux accompanied by the temperature rise, 0.03 parts by weight of the third isoammonium peroxydecanoate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 3.34 parts by weight. In the toluene, while 0.06 parts by weight of the above-mentioned third amyl isophthalate was dissolved, the solution polymerization was carried out under reflux at about 105 to 110 ° C, and then aging was carried out for 4 hours.

Next, 0.045 parts by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for the cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Next, after further heating at 240 ° C for 90 minutes in an autoclave, 5 parts by weight of an acrylonitrile-styrene (AS) copolymer was added to the obtained polymerization solution. Next, the polymerization solution to which the AS copolymer was added was dried at 240 ° C for 1 hour under reduced pressure to obtain a transparent resin (E) mixed with a (meth)acrylic polymer and an AS copolymer having a lactone ring structure in the main chain. ).

The obtained resin (E) was press-formed at 250 ° C into a film having a thickness of 120 μm by a press molding machine, and the obtained film was subjected to an autostereograph (manufactured by Shimadzu Corporation) at a stretching temperature of 142 ° C. One-axis stretching was performed so that the stretching ratio was doubled. The phase difference of the obtained stretched film was evaluated by using a fully automatic birefringence meter (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.), and as a result, the in-plane phase difference of 100 μm in thickness was about 10 nm in the range of the measurement wavelength of 447 nm to 750 nm. the following.

(Manufacturing Example 12)

10 parts by weight of methyl 2-(hydroxymethyl)acrylate (MHMA), 40 parts by weight of methyl methacrylate (MMA), and 50 parts by weight of toluene as a polymerization solvent, equipped with a stirring device, temperature In the reaction apparatus of the sensor, the cooling tube, and the nitrogen gas introduction tube, the temperature was raised to 105 ° C while nitrogen gas was supplied thereto. At the beginning of the reflux accompanied by the temperature rise, 0.03 parts by weight of the third isoammonium peroxydecanoate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 3.34 parts by weight. In the toluene, while 0.06 parts by weight of the above-mentioned third amyl isophthalate was dissolved, the solution polymerization was carried out under reflux at about 105 to 110 ° C, and then aging was carried out for 4 hours.

Next, 0.045 parts by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for the cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Subsequently, the mixture was further heated at 240 ° C for 90 minutes in an autoclave, and the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a transparent polymer (B-2E) having a lactone ring structure in its main chain.

(Manufacturing Example 13)

70 parts by weight of methyl 2-(hydroxymethyl)acrylate (MHMA), 380 parts by weight of methyl methacrylate (MMA), 50 parts by weight of N-vinyl-2-pyrrolidone, and 250 parts by weight as a polymerization solvent The toluene and 250 parts by weight of methyl isobutyl ketone were placed in a reaction apparatus equipped with a stirring device, a temperature sensor, a cooling tube, and a nitrogen introduction tube, and the temperature was raised to 80 ° C while passing nitrogen gas. . After the temperature of the polymerization system was stably maintained at 80 ° C, 1 part by weight of a solution of 2,2'-azobis(2-methylbutyronitrile) dissolved in 10 parts by weight of toluene as a polymerization initiator was added. Then, the solution polymerization was carried out for 8 hours while maintaining the polymerization system at 83 °C.

Next, 0.5 part by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for the cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Subsequently, the mixture was further heated at 240 ° C for 90 minutes in an autoclave, and the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a N-vinyl-2-pyrrolidone unit as a inherently negative polymer. A constituent unit of birefringence and having a lactone ring structure as a constituent unit of a transparent copolymer (B-3C) which imparts a positive intrinsic birefringence to a polymer.

(Example 13)

The polymer (B-2D) obtained in Production Example 9 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 120 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 145 ° C using the above-described autostereoscopic plotter so that the stretching ratio in the MD direction was 2.5 times, and a stretched film (F16) having a thickness of 100 μm was obtained. .

In addition, 5 parts by weight of the polymer (B-1D) obtained in Production Example 10 was uniformly mixed with a mixed solvent of methyl ethyl ketone, toluene, and chloroform, and manufactured in Production Example 11. After 95 parts by weight of the resin (E), the obtained resin was dried to replace the polymer (B-2D), and a stretched film (F17) having a thickness of 95 μm was obtained in the same manner as above. Among them, the stretching ratio was 2 times and the stretching temperature was 132 °C.

Next, one stretched film (F16) and four stretched films (F17) were laminated while aligning the stretch direction (stretching axis) of each film. The wavelength dispersion of the phase difference (in-plane phase difference) in the obtained stretched film laminate was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 23 below.

As shown in Table 23, the stretched film laminate produced in Example 13 showed a reverse wavelength dispersion in which the phase difference was smaller as the wavelength of light was shorter.

(Example 14)

18 parts by weight of the polymer (B-2E) obtained in Production Example 12 and 2 parts by weight of the polymer (B-1D) obtained in Production Example 10 were dissolved in methyl ethyl ketone, toluene, and chloroform. The mixed solvent was stirred, and the polymer (B-2E) and (B-1D) were uniformly mixed. Next, the obtained mixed solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a resin containing the polymers (B-2E) and (B-1D).

Next, the obtained resin was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 100 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 139 ° C by the above-described autostereoscopic plotter so that the stretching ratio in the MD direction was doubled, and a stretched film having a thickness of 60 μm was obtained.

The wavelength dispersion of the phase difference (in-plane phase difference) of the obtained stretched film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 24 below.

As shown in Table 24, the stretched film obtained in Example 14 showed the reverse wavelength dispersion in which the phase difference was smaller as the wavelength of light was shorter.

(Example 15)

The copolymer (B-3C) obtained in Production Example 13 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 100 μm. Then, the obtained film was subjected to one-axis stretching at a stretching temperature of 130 ° C by the above-described autostereoscopic plotter so that the stretching ratio in the MD direction was doubled, and a stretched film having a thickness of 60 μm was obtained.

The wavelength dispersion of the phase difference (in-plane phase difference) of the obtained stretched film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 25 below.

As shown in Table 25, the stretched film obtained in Example 15 showed the reverse wavelength dispersion in which the phase difference was smaller as the wavelength of light was shorter.

(Comparative Example 11)

The stretched film (F16) obtained in Example 13 (composed of the polymer (B-2D) obtained in Production Example 9), the wavelength dispersion of the phase difference (in-plane phase difference) was carried out Example 1 was evaluated in the same manner. The evaluation results are shown in Table 26 below.

As shown in Table 26, the stretched film (F16) showed a wavelength dispersion in which the phase difference was larger as the wavelength of light was shorter.

In addition, the alignment angle of the stretched film (F16) was evaluated by using a fully automatic birefringence meter (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.), and as a result, the phase angle (Φ) was -0.7°. That is, the intrinsic birefringence of the polymer (B-2D) obtained in Production Example 9 was a positive value.

(Comparative Example 12)

The stretched film (F17) obtained in Example 13 (composed of the polymer (B-1D) obtained in Production Example 10 and the resin (E) obtained in Production Example 11) had a phase difference ( The wavelength dispersion of the in-plane phase difference) was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 27 below.

As shown in Table 27, the stretched film (F17) showed wavelength dispersion in which the wavelength of light was shorter and the phase difference was larger, and the wavelength dispersion property was considerably large.

In addition, the alignment angle of the stretched film (F17) was evaluated by using a fully automatic birefringence meter (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.), and the phase angle (Φ) was -86.4 °. That is, the intrinsic birefringence of the resin obtained by mixing 5 parts by weight of the polymer (B-1D) obtained in Production Example 10 and 95 parts by weight of the resin (E) obtained in Production Example 11 was a negative value.

(Manufacturing Example 14)

25 parts by weight of MHMA, 63 parts by weight of MMA, 5 parts by weight of cyclohexyl methacrylate (CHMA), 7 parts by weight of vinyl carbazole, and 90 parts by weight of toluene as a polymerization solvent, with stirring In the reaction apparatus of the apparatus, the temperature sensor, the cooling tube, and the nitrogen gas introduction tube, the temperature was raised to 105 ° C while introducing nitrogen gas. At the beginning of the reflux accompanied by the temperature rise, 0.04 parts by weight of the third isoammonium peroxydecanoate (product name: Luperox 570, manufactured by ARKEMA Co., Ltd.) as a polymerization initiator was added, on the one hand, 10 parts by weight. In the toluene, while 0.08 parts by weight of the above-mentioned third amyl isophthalate was dissolved, the solution polymerization was carried out under reflux at about 105 to 110 ° C, and then heating and aging were carried out for 4 hours. .

Next, 0.9 parts by weight of a octyl phosphate/dioctyl ester mixture as a catalyst for a cyclization condensation reaction (cyclization catalyst) was added to the obtained polymerization solution, followed by reflux at about 80 to 105 ° C for 2 hours. Cyclization condensation reaction.

Then, after further heating at 240 ° C for 90 minutes in an autoclave, the obtained polymerization solution was dried at 240 ° C for 1 hour under reduced pressure to obtain a composition having a vinyl carbazole unit as a negative intrinsic birefringence imparted to the polymer. The unit has a lactone ring structure as a transparent copolymer (B-3D) which is a constituent unit which imparts positive intrinsic birefringence to the polymer.

(Embodiment 16)

The copolymer (B-3D) obtained in Production Example 14 was press-formed at 250 ° C by a press molding machine to obtain a film having a thickness of about 190 μm. Then, the obtained film was stretched at any stretching end at a stretching temperature of 147 ° C by the above-described autostereoscopic plotter so that the stretching ratio was doubled, and a stretched film having a thickness of 130 μm was obtained.

The wavelength dispersion of the phase difference of the obtained stretched film was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 28 below.

As shown in Table 28, the stretched film obtained in Example 16 showed that the shorter the wavelength of light, the smaller the phase difference and the reverse wavelength dispersion property, and the change was considerable.

The present invention can be applied to other embodiments as long as it does not distract from its intent and essential features. The embodiments disclosed in the present specification are intended to describe various elements and are not limited thereto. The scope of the present invention is defined by the scope of the claims

Industrial availability

The optical film of the present invention can be widely used in an image display device including a liquid crystal display device (LCD) or an organic EL display (OLED), similar to the conventional optical film having birefringence. Further, by using the optical film of the present invention, the display characteristics of the image display device can be improved.

1, 11, 21, 31. . . Optical film

2, 12, 22, 23, 32. . . Floor

Fig. 1 is a cross-sectional view schematically showing an example of an optical member of the present invention.

Fig. 2 is a cross-sectional view schematically showing another example of the optical member of the present invention.

Fig. 3 is a cross-sectional view schematically showing still another example of the optical member of the present invention.

Fig. 4 is a cross-sectional view schematically showing still another example of the optical member of the present invention.

Claims (37)

An optical film having a layer composed of a resin (A) having a heterocyclic aromatic group; at least in the visible light region, the shorter the wavelength, the smaller the wavelength dispersion of the birefringence; the optical a film-based phase difference plate; the resin (A) having a polymer (B-1) containing an α,β-unsaturated monomer unit having a heterocyclic aromatic group as a constituent unit; The intrinsic birefringence of the polymer (B-1) is a negative value; the resin (A) further contains a polymer (B-2) having a positive intrinsic birefringence. The optical film of claim 1, wherein the resin (A) is an acrylic resin or a cyclic olefin resin. The optical film of claim 1, wherein the resin (A) contains a polymer (B-1) having a constituent unit derived from a monomer having a molecular weight of 450 nm or more The visible light region does not have a peak of the absorption spectrum, and the maximum value of the molar absorption coefficient in the wavelength band of 300 to 450 nm is 3000 L/(mol ‧ cm) or more. The optical film of claim 1, wherein the α,β-unsaturated monomer unit is at least one selected from the group consisting of a vinyl carbazole unit, a vinyl pyridine unit, a vinylimidazole unit, and an ethylene thiophene unit. The optical film of claim 1, wherein the α,β-unsaturated monomer unit is a vinylcarbazole unit. An optical film according to claim 1, wherein the polymer (B-2) has a ring structure in the main chain. The optical film of claim 6, wherein the polymer (B-2) is at least one selected from the group consisting of a cyclic olefin polymer and a cellulose derivative. The optical film of claim 6, wherein the polymer (B-2) is a (meth)acrylic polymer having a ring structure in the main chain. An optical film according to claim 8 wherein the ring structure is selected from the group consisting of a glutaric anhydride structure, a maleic anhydride structure or an N-substituted maleimide. At least one of the constructs. The optical film of claim 8, wherein the ring structure is selected from the group consisting of a lactone ring structure and at least one of a pentylene imine structure. The optical film of claim 1, wherein the polymer (B-1) has a vinyl carbazole unit as a constituent unit; the polymer (B-2) has a lactone ring structure selected from the group consisting of a lactone ring structure and a pentylene group. A ring structure of at least one of the quinone imine structures. An optical film having a layer composed of a resin (A) having a heterocyclic aromatic group; at least in the visible light region, the shorter the wavelength, the smaller the wavelength dispersion of the birefringence; the optical a film-based phase difference plate; the resin (A) having a polymer (B-1) containing an α,β-unsaturated monomer unit having a heterocyclic aromatic group as a constituent unit; The intrinsic birefringence of the resin (A) is negative and further has an inherent double A layer composed of a resin (C) having a positive refractive index is a laminated structure including a layer composed of the resin (A) and a layer composed of the resin (C). The optical film of claim 12, wherein the resin (A) is an acrylic resin or a cyclic olefin resin. The optical film of claim 12, wherein the resin (A) contains a polymer (B-1) having a constituent unit derived from a monomer having a molecular weight of 450 nm or more The visible light region does not have a peak of the absorption spectrum, and the maximum value of the molar absorption coefficient in the wavelength band of 300 to 450 nm is 3000 L/(mol ‧ cm) or more. The optical film of claim 12, wherein the α,β-unsaturated monomer unit is at least one selected from the group consisting of a vinyl carbazole unit, a vinyl pyridine unit, a vinylimidazole unit, and an ethylene thiophene unit. The optical film of claim 12, wherein the α,β-unsaturated monomer unit is a vinylcarbazole unit. The optical film of claim 12, wherein the resin (C) is a polymer (B-2) having a positive intrinsic birefringence. The optical film of claim 17, wherein the polymer (B-2) has a ring structure in the main chain. The optical film of claim 18, wherein the polymer (B-2) is at least one selected from the group consisting of a cyclic olefin polymer and a cellulose derivative. The optical film of claim 18, wherein the polymer (B-2) is a (meth)acrylic polymer having a ring structure in the main chain. An optical film according to claim 20, wherein the ring structure It is selected from at least one of a glutaric anhydride structure, a maleic anhydride structure, or an N-substituted maleimide structure. The optical film of claim 20, wherein the ring structure is selected from at least one of a lactone ring structure and a pentaneimine structure. The optical film of claim 12, wherein the polymer (B-1) has a negative intrinsic birefringence. The optical film of claim 12, wherein the polymer (B-1) has a vinyl carbazole unit as a constituent unit and has a negative intrinsic birefringence. The optical film of claim 17, wherein the polymer (B-1) has a vinyl carbazole unit as a constituent unit and has a negative intrinsic birefringence; the polymer (B-2) has a choice in the main chain A ring structure of at least one of a lactone ring structure and a pentamethylene imine structure. An optical film having a layer composed of a resin (A) having a heterocyclic aromatic group; at least in the visible light region, the shorter the wavelength, the smaller the wavelength dispersion of the birefringence; the optical a film-based phase difference plate; the resin (A) having a polymer (B-1) containing an α,β-unsaturated monomer unit having a heterocyclic aromatic group as a constituent unit; The polymer (B-1) has a unit of an α,β-unsaturated monomer having a heterocyclic aromatic group as a constituent unit having a function of imparting a negative intrinsic birefringence to the polymer, and further has a production unit. Giving the polymer a constituent unit of the action of the positive intrinsic birefringence; the constituent unit capable of imparting a positive intrinsic birefringence is selected from a (meth) acrylate unit, a ring structure as a derivative of a (meth) acrylate unit, And at least one of the cyclic olefin units. The optical film of claim 26, wherein the resin (A) is an acrylic resin or a cyclic olefin resin. The optical film of claim 26, wherein the resin (A) contains a polymer (B-1) having a constituent unit derived from a monomer of 450 nm or more. There is no peak of the absorption spectrum in the visible light region; the maximum value of the molar absorption coefficient in the wavelength band of 300-450 nm is 3000 L/(mol ‧ cm) or more. The optical film of claim 26, wherein the α,β-unsaturated monomer unit is at least one selected from the group consisting of a vinyl carbazole unit, a vinyl pyridine unit, a vinylimidazole unit, and an ethylene thiophene unit. An optical film according to claim 26, wherein the α,β-unsaturated monomer unit is a vinylcarbazole unit. An optical film according to claim 26, wherein the constituent unit which produces an effect of imparting positive intrinsic birefringence to the polymer (B-1) is selected from (meth) acrylate units, and as (methyl) At least one of the ring structures of the derivatives of the acrylate units. The optical film of claim 31, wherein the ring structure is a lactone ring structure. An optical film as claimed in claim 26, wherein the polymer (B-1) has a vinyl carbazole unit as a constituent unit having an action of imparting negative intrinsic birefringence, and further has a lactone ring structure as a constituent unit having an action of imparting positive intrinsic birefringence. An image display device comprising the optical film of any one of claims 1 to 33. A method for producing an optical film for producing an optical film of claim 12; a stretched film composed of the resin (A) and a stretched film composed of the resin (C) are laminated to obtain a laminated structure In the optical film, the laminated structure contains a layer composed of the resin (A) and a layer composed of the resin (C). The method for producing an optical film according to claim 35, wherein the resin (C) contains a polymer (B-2) having positive intrinsic birefringence. A method for producing an optical film for producing an optical film of claim 12; stretching a laminate film comprising the resin (A) and a precursor film comprising the resin (C) An optical film having a laminated structure containing a layer composed of the resin (A) and a layer composed of the resin (C) was obtained.